From Today, I'm a Player - Chapter 261. Ragnarok Pt. 3

The world that nurtured the civilization which reached the pinnacle of magic was on the verge of destruction.
The last survivor transmigrated to the past, when the magic civilization started growing, as countless mages were still fumbling their ways through the thorny paths of magic knowledge.
He, who came from the end of the magic era, aim to reach the pinnacle of magic.

- Description from Novelupdates

Volume 1 (Set between volumes 13 and 14)

A series of short stories set before the events of volume fourteen including how Team GROUP was formed.

Volume 2 (Set between volumes 16 and 17)

A series of short stories including two separate meetings between Touma’s and Mikoto’s parents, two tales involving two of the Level 5s of Academy City, and other funny stories involving some of the characters.

As soon as she fell into the world of beastmen, a leopard forcibly took her back to his home. Indeed, Bai Qingqing is at a complete and utter loss. The males in this world are all handsome beyond compare, while the women are all so horrid that even the gods shudder at their sight. As a first-rate girl from the modern world (she’s also a quarter Russian), Bai Qingqing finds herself sitting at the center of a harem filled with beautiful men — at the very peak of existence.

Three Emperors have died in quick succession. The prince whom nobody had taken notice of unexpectedly succeeds to the throne. He is quickly plunged into layers upon layers of danger. The Empress Dowager dislikes him, wishing to install a younger, more obedient Emperor. His half-brother dislikes him, accusing him of stealing the throne that is rightfully his. The palace attendants and servants dislike him, believing that he is not a true Emperor. The Child Emperor must save himself.